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Hossain MS, Begum SMKN, Rahman MM, Parvez M, Mazumder RN, Sarker SA, Hasan MM, Fahim SM, Gazi MA, Das S, Mahfuz M, Ahmed T. Environmental enteric dysfunction and small intestinal histomorphology of stunted children in Bangladesh. PLoS Negl Trop Dis 2023; 17:e0010472. [PMID: 36656867 PMCID: PMC9888706 DOI: 10.1371/journal.pntd.0010472] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 01/31/2023] [Accepted: 01/10/2023] [Indexed: 01/20/2023] Open
Abstract
There is lack of information on the histological characteristics of the intestinal mucosa in Bangladeshi children. Collection of intestinal biopsy samples and assessment of the histomorphological features is considered to be the traditional gold standard for diagnosis of environmental enteric dysfunction (EED). The purpose of the study was to evaluate the intestinal histological characteristics of stunted children aged between 12-18 months with possible EED. 110 children with chronic malnutrition (52 stunted with length-for-age Z score, LAZ<-2 and 58 at risk of stunting with LAZ <-1 to -2) from the Bangladesh Environmental Enteric Dysfunction (BEED) study protocol who underwent upper gastrointestinal (GI) endoscopy were selected for this study. To explore the association of EED with childhood stunting, upper GI endoscopy was done and the biopsy specimens were studied for histopathology. Villous height and crypt depth were measured and the presence and intensity of inflammatory infiltrates in the lamina propria was investigated. Bivariate analysis was performed to examine the relationship between stunting and histologic morphology. More than 90% children irrespective of nutritional status were diagnosed to have chronic non-specific duodenitis on histopathology. Half of the children from both groups had villous atrophy as well as crypt hyperplasia and lymphocytic infiltration was present in more than 90% children, irrespective of groups. However, no statistically significant difference was observed when compared between the groups. The prevalence of chronic non-specific duodenitis in Bangladeshi children, irrespective of nutritional status, was high. A significant number of these children had abnormal findings in intestinal histomorphology. Trial registration number: ClinicalTrials.gov ID: NCT02812615 Date of first registration: 24/06/2016. https://clinicaltrials.gov/ct2/results?cond=NCT02812615&term=&cntry=&state=&city=&dist.
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Affiliation(s)
- Md. Shabab Hossain
- Nutrition and Clinical Services Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
- * E-mail:
| | | | - M Masudur Rahman
- Department of Gastroenterology, Sheikh Russel National Gastroliver Institute and Hospital, Dhaka, Bangladesh
| | - Mashud Parvez
- Department of Pathology, Bangladesh Specialized Hospital, Dhaka, Bangladesh
| | - Ramendra Nath Mazumder
- Nutrition and Clinical Services Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Shafiqul Alam Sarker
- Nutrition and Clinical Services Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Md. Mehedi Hasan
- Nutrition and Clinical Services Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Shah Mohammad Fahim
- Nutrition and Clinical Services Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Md. Amran Gazi
- Nutrition and Clinical Services Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Subhasish Das
- Nutrition and Clinical Services Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Mustafa Mahfuz
- Nutrition and Clinical Services Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Tahmeed Ahmed
- Nutrition and Clinical Services Division, International Centre for Diarrheal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Public Health Nutrition, James P Grant School of Public Health, BRAC University, Dhaka, Bangladesh
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Mahmud S, Gulshan J, Parvez M, Tasneem F, Ahmed SS. Correction to: Etiology and outcome of neonatal cholestasis: an experience in a tertiary center of Bangladesh. Egypt Liver Journal 2022. [DOI: 10.1186/s43066-022-00180-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Mahmud S, Gulshan J, Parvez M, Tasneem F, Ahmed SS. Etiology and outcome of neonatal cholestasis: an experience in a tertiary center of Bangladesh. Egypt Liver Journal 2022. [DOI: 10.1186/s43066-021-00168-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Neonatal cholestasis (NC) is a major cause of morbidity and mortality in young infants. This study examines the etiology of NC and its outcome during 2 years of follow-up at a tertiary referral center in Bangladesh.
Results
Out of 80 cholestatic infants, 60% had intrahepatic cholestasis with a mean age of onset of 12.4±2.8 days and a mean age of admission of 82.4±29.0 days. The remaining 40% were extrahepatic with a mean age of onset of 6.7±2.3 days and a mean age of admission of 94.6±50.4 days. Biliary atresia (BA), idiopathic neonatal hepatitis (INH), and TORCH (Toxoplasma, rubella, cytomegalovirus, and herpes simplex) infection except rubella were the most common causes. After receiving treatment, 46.2% of the cases improved, 23.8% deteriorated with morbidity, and 30% died. The majority of the children with INH, TORCH, choledochal cyst, hypothyroidism, galactosemia, and urinary tract infection (UTI) with sepsis were improved. Significant mortality was found in BA (56.6%), intrahepatic bile duct paucity (PIBD) (100%), and progressive familial intrahepatic cholestasis (PFIC) (100%) whereas the rest of BA (43.4%) live with persistent morbidity. Significant clinical improvement was observed in 37 (46.2%) cases of cholestasis evidenced by decreasing jaundice, change of color of urine from dark to normal color, change of stool color from pale to yellow, and gradual decrease in liver size from hepatomegaly state. In addition, decreasing median total bilirubin, direct bilirubin, alanine transaminase, gamma-glutamyl transferase, and alkaline phosphatase showed biochemical improvement at 2 years follow-up. The age of admission, etiology, and presence of ascites are the predictors of outcomes.
Conclusion
BA was the most common cause of extrahepatic while INH and TORCH infection were the most common cause of intrahepatic cholestasis. Majority of children with intrahepatic cholestasis improved but deteriorated with BA and genetic causes. Prompt referral and early diagnosis as well as the etiology of NC were the main determinants of the favorable outcome.
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Hossain MS, Begum SMKN, Rahman MM, Mazumder RN, Parvez M, Gazi MA, Hasan MM, Fahim SM, Das S, Mahfuz M, Sarker SA, Ahmed T. Alterations in the histological features of the intestinal mucosa in malnourished adults of Bangladesh. Sci Rep 2021; 11:2355. [PMID: 33504937 PMCID: PMC7840936 DOI: 10.1038/s41598-021-82079-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/13/2021] [Indexed: 12/20/2022] Open
Abstract
There is paucity of knowledge on the histological features of the intestinal mucosa in malnourished adults of Bangladesh. The purpose of the study was to explore the histological features of the intestinal mucosa in malnourished adults of Bangladesh and to compare the findings with their well-nourished counterparts. 64 adults (37 malnourished with body mass index, BMI < 18.5 kg/m2 and 27 controls with BMI > 18.5 kg/m2) from the Bangladesh Environmental Enteric Dysfunction (BEED) study, who underwent upper-gastrointestinal endoscopy, were selected for this study. With a view to address the association of environmental enteric dysfunction (EED) with malnutrition, upper-gastrointestinal endoscopy was performed and mucosal biopsies from the distal duodenum were studied for histopathology. Villous height, crypt depth, and presence of inflammatory infiltrates in lamina propria were investigated. Bivariate analysis was performed to quantify the relation between malnutrition and the histological features. About 95% adults, irrespective of nutritional status, were diagnosed to have chronic non-specific duodenitis on histopathology. Malnourished adults suffered significantly more from chronic active duodenitis compared to their well-nourished counterparts (p = 0.003). Malnourished adults also had significantly higher frequency of subtotal villous atrophy, crypt hyperplasia and marked cellular infiltration in the lamina propria than the healthy controls (p < 0.05).
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Affiliation(s)
- Md Shabab Hossain
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), 68, Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka, 1212, Bangladesh.
| | | | - M Masudur Rahman
- Department of Gastroenterology, Sheikh Russel National Gastroliver Institute and Hospital, Dhaka, 1212, Bangladesh
| | - Ramendra Nath Mazumder
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), 68, Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka, 1212, Bangladesh
| | - Mashud Parvez
- Department of Pathology, Bangladesh Specialized Hospital, Dhaka, 1207, Bangladesh
| | - Md Amran Gazi
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), 68, Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka, 1212, Bangladesh
| | - Md Mehedi Hasan
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), 68, Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka, 1212, Bangladesh
| | - Shah Mohammad Fahim
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), 68, Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka, 1212, Bangladesh
| | - Subhasish Das
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), 68, Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka, 1212, Bangladesh
| | - Mustafa Mahfuz
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), 68, Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka, 1212, Bangladesh
| | - Shafiqul Alam Sarker
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), 68, Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka, 1212, Bangladesh
| | - Tahmeed Ahmed
- Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), 68, Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka, 1212, Bangladesh
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Thériault KD, Radford C, Parvez M, Heyne B, Sutherland TC. Structure–property relationship of donor–acceptor acridones – an optical, electrochemical and computational study. Phys Chem Chem Phys 2015. [DOI: 10.1039/c5cp03222a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The effect of changing acceptor strength on intramolecular charge transfer absorption and its implication towards organic materials are investigated.
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Affiliation(s)
| | - C. Radford
- Department of Chemistry
- University of Calgary
- Calgary
- Canada
| | - M. Parvez
- Department of Chemistry
- University of Calgary
- Calgary
- Canada
| | - B. Heyne
- Department of Chemistry
- University of Calgary
- Calgary
- Canada
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Waheed A, Bhat S, Parvez M. Introduction of bundle of care and effect on surgical site infections in patients taken for elective surgical procedures. Crit Care 2014. [PMCID: PMC4273845 DOI: 10.1186/cc14034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
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Kamal R, Natrajan M, Katoch K, Parvez M, Nag VK, Dayal R. Evaluation of the diagnostic value of immunocytochemistry and in situ hybridization in the pediatric leprosy. Indian J Lepr 2013; 85:109-114. [PMID: 24724232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Leprosy is characterized by a long and variable incubation period and a chronic clinical course. Diagnosis of leprosy is essentially based on clinical features. Although the majority of cases can be diagnosed clinically yet alternative methods for diagnosis are required especially for early cases. Immunocytochemistry and in situ hybridization can be a valuable tool for diagnosis for early cases. The present study is aimed to assess the diagnostic value of immunocytochemistry and in situ hybridization in cytological specimens and to compare these techniques with Z.N. staining. This prospective study was carried out in 26 patients below 18 years of age of leprosy. Clinical examination of each patient was done and categorized according to IAL. After taking consent, three skin smears was taken, one for Z.N. staining and remaining two for immunocytochemistry and in situ hybridization respectively. Routine skin smear examination by Z.N. staining method confirmed the diagnosis in 4/26 (15.83%) and these belonged to BB, BL category. Immunocytochemistry showed positivity in 10/15 (66.6%) in BT and 72.7% in BB/BL leprosy. Immunocytochemistry improved the diagnosis by 53.85%, and the results were statistically significant (p < 0.01). In situ hybridization showed the positive results in 80% cases of BT leprosy and 90.9% cases of BB/BL leprosy. In situ hybridization improved the diagnosis by 70% in comparison to ZN staining and the results were statistically significant (p < 0.01). This study supports that immunocytochemistry and in situ hybridization enhance the diagnosis of leprosy when compared to routine skin smears stained by Z.N staining. They are important diagnostictoolsfor definitive diagnosis in early as well as established cases of leprosy.
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Parvez M, Lohr TL, Piers WE. Potential Pt-complexes for catalytic water splitting. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311089185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Parvez M, Hobbs M, Roesler R. Iridium and zirconium formamidinates as precursors for novel stable carbenes. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308087059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Steinke DR, Majak W, Sorensen TS, Parvez M. Chelation of molybdenum in Medicago sativa (alfalfa) grown on reclaimed mine tailings. J Agric Food Chem 2008; 56:5437-5442. [PMID: 18543934 DOI: 10.1021/jf800489c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Extraction and analytical procedures were developed from 1999 to 2005 for the chemical investigation of molybdenum (Mo) in aerial portions of alfalfa ( Medicago sativa L.) grown on a reclaimed mine tailings site at the Highland Valley Copper Mine in British Columbia, Canada. The purification procedures were guided by colorimetric analyses specific for Mo. The Mo levels in freeze-dried plant samples exceeded 100 ppm, which is more than 20 times the maximum level recommended for livestock feed. In contrast to previous work, which detected the inorganic molybdate anion (MoO4(2-)) in alfalfa from the site, the present study identified the major pool of Mo as a chelate bound to malic acid in five sources of plant material. However, the inorganic form of Mo was characterized in aqueous tailings samples, but once imbibed by vegetation, the anion was chelated to the alpha-hydroxy organic acid. Synthetic chelates were synthesized to differentiate the Mo-malate complex from the Mo-citrate by 95Mo NMR. Crystal structure of the synthetic Mo-malate determined that the Mo was bound to two malato ligands as Na 2[MoO2(malate) 2] x 5H2O, which confirmed the structure of the isolates deduced by 95Mo NMR. The chelation of Mo at the site may well explain the apparent lack of long-term clinical effects in cattle grazing the site.
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Affiliation(s)
- D R Steinke
- Agriculture and Agri-Food Canada, 3015 Ord Road, Kamloops, B.C., Canada.
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Shahzadi S, Ali S, Parvez M, Badshah A, Ahmed E, Malik A. Synthesis, spectroscopy and antimicrobial activity of vanadium(III) and vanadium(IV) complexes involving Schiff bases derived from Tranexamic acid and X-ray structure of zwitter ion of Tranexamic acid. RUSS J INORG CHEM+ 2007. [DOI: 10.1134/s0036023607030163] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Affiliation(s)
- O. N. Ogbeide
- a Chemistry Department , University of Benin , P. M. B. 1154, Benin City , Nigeria
| | - M. Parvez
- a Chemistry Department , University of Benin , P. M. B. 1154, Benin City , Nigeria
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Parvez M, Krahulic KE, Ly HV, Forster TD, Roesler R. Novel five-membered B-N-C heterocycles. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305087258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Chivers T, Fedorchuk C, Parvez M. Synthetic and Structural Investigations of Monomeric Dilithium Boraamidinates and Bidentate NBNCN Ligands with Bulky N-Bonded Groups. Inorg Chem 2004; 43:2643-53. [PMID: 15074983 DOI: 10.1021/ic0352755] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dilithiated boraamidinate complexes [Li(2)[PhB(NDipp)(2)](THF)(3)] (7a) (Dipp = 2,6-diisopropylphenyl) and [Li(2)[PhB(NDipp)(N(t)Bu)](OEt(2))(2)] (7b), prepared by reaction of PhB[N(H)Dipp][N(H)R'] (6a, R' = Dipp; 6b, R' = (t)Bu) with 2 equiv of (n)BuLi, are shown by X-ray crystallography to have monomeric structures with two terminal and one bridging THF ligands (7a) or two terminal OEt(2) ligands (7b). The derivative 7a is used to prepare the spirocyclic group 13 derivative [Li(OEt(2))(4)][In[PhB(NDipp)(2)](2)] (8a) that is shown by an X-ray structural analysis to be a solvent-separated ion pair. The monoamino derivative PhBCl[N(H)Dipp] (9a), obtained by the reaction of PhBCl(2) with 2 equiv of DippNH(2), serves as a precursor for the synthesis of the four-membered BNCN ring [[R'''N(H)](Ph)B(mu-N(t)Bu)(2)C(n)Bu] (10a, R''' = Dipp). The X-ray structures of 6a, 9a, and 10a have been determined. The related derivative 10b (R''' = (t)Bu) was synthesized by the reaction of [Cl(Ph)B(mu-N(t)Bu)(2)C(n)Bu] with Li[N(H)(t)Bu] and characterized by (1)H, (11)B, and (13)C NMR spectra. In contrast to 10a and 10b, NMR spectroscopic data indicate that the derivatives [[DippN(H)](Ph)B(NR')(2)CR(NR')] (11a: R =( t)Bu, R' = Cy; 11b: R = (n)Bu, R' = Dipp) adopt acyclic structures with three-coordinate boron atoms. Monolithiation of 10a produces the novel hybrid boraamidinate/amidinate (bamam) ligand [Li[DippN]PhB(N(t)Bu)C(n)Bu(N(t)Bu)] (12a).
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Affiliation(s)
- T Chivers
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
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Hayes TK, Freyer AJ, Parvez M, Weinreb SM. Transition metal-promoted intramolecular cyclizations of .alpha.,.alpha.-dichloro esters and acids. J Org Chem 2002. [DOI: 10.1021/jo00376a109] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Clark HC, Ferguson G, Jain VK, Parvez M. Organoplatinum(IV) compounds. 1. Preparation and characterization of dimethylplatinum(IV) compounds with chelating nitrogen donor ligands. Crystal and molecular structures of dimethyl[bis(1-pyrazolyl)methane]platinum diiodide and dimethyl[bis(3,5-dimethyl-1-pyrazolyl)methane]platinum diiodide. Organometallics 2002. [DOI: 10.1021/om50001a004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Buergi HB, Fischer E, Kunz RW, Parvez M, Pregosin PS. Correlation between NMR coupling constants and molecular structure. Synthesis and phosphorus-31 NMR measurements of [HgX2(cis-Ph2PCH:CHPPh2)] and x-ray crystal structures of [HgBr2(cis-Ph2PCH:CHPPh2)], [Hg(NO3)2(PPh3)2], and [Hg(CN)2(PPh3)2]. Inorg Chem 2002. [DOI: 10.1021/ic00133a074] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bell SI, Parvez M, Weinreb SM. Metalation and alkylation of 3,6-dihydrothiazine 1-oxides prepared via Diels-Alder cycloadditions of N-sulfinyl dienophiles. J Org Chem 2002. [DOI: 10.1021/jo00001a068] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Masters AP, Parvez M, Sorensen TS, Sun F. Attempted Generation of an Observable Ethano-Bridged (Cyclopentyl) Oxyallyl. The Pericyclic Nature of an Oxyallyl-Oxyallyl Dimerization Reaction. J Am Chem Soc 2002. [DOI: 10.1021/ja00086a013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Funk RL, Olmstead TA, Parvez M. A solution to the in,out-bicyclo[4.4.1]undecan-7-one problem inherent in ingenane total synthesis. J Am Chem Soc 2002. [DOI: 10.1021/ja00218a049] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Back TG, Bethell RJ, Parvez M, Taylor JA. Preparation of vinylogous 2-sulfonylindolines by the palladium-catalyzed heteroannulation of o-iodoanilines with dienyl sulfones and their further transformation to indoles and carbazoles. J Org Chem 2001; 66:8599-605. [PMID: 11735543 DOI: 10.1021/jo016080m] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The palladium-catalyzed heteroannulation of o-iodoanilines with dienyl sulfones provides a convenient route to vinylogous 2-sulfonylindolines 3. The reaction proceeds in DMF/water in the presence of potassium carbonate and catalytic palladium(II) acetate and is compatible with both electron-donating and -withdrawing substituents in the para position of the aniline, and with an alkyl substituent at C-2 of the dienyl sulfone. The indolines underwent oxidation with DDQ to afford the corresponding indoles 4. The latter were then employed as dienes in Diels-Alder reactions with dimethyl acetylenedicarboxylate (DMAD), methyl propiolate, or methyl acrylate. In the case of the latter two dienophiles, the cycloadditions were highly regioselective, affording the corresponding 1,3-products (with respect to the relative positions of the sulfone and ester groups), exclusively. The cycloadducts from acetylenic dienophiles were converted to the corresponding carbazoles by elimination of the sulfone moiety with DBU, and that from methyl acrylate was subjected to reductive desulfonylation and oxidation to the corresponding carbazole with DDQ. The method thus provides access to carbazoles with various substituents at the 3-, 4-, and 6-positions.
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Affiliation(s)
- T G Back
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
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Taeschler C, Parvez M, Sorensen TS. Preparation of the tricyclo[5.3.1.13,9]dodeca-1,5-diyl dication: attempts to prepare a novel µ-H cation. J PHYS ORG CHEM 2001. [DOI: 10.1002/poc.453] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
The silver sulfonate network presented herein, silver 3-pyridinesulfonate, reversibly and selectively absorbs MeCN while undergoing a major structural rearrangement. The origin of this structural flexibility is a coupling of the weak coordinating ability of the SO3 group with the geometrically pliant silver(I) center. Single crystal and powder X-ray structures of both the desolvated and solvated forms are presented in addition to the mechanism of their reversible interconversion. A heterogeneous gas chromatographic study showing selective extraction of the MeCN is also presented. Extended solid frameworks which reorder to any extent are not common but the structure presented herein transforms from a tetragonal to a triclinic crystal system. The results indicate that cooperative interactions in systems based on supposedly weaker interactions can yield softer yet functional networks with behavior unlike that observed in more rigid inorganic frameworks.
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Affiliation(s)
- S K Mäkinen
- Department of Chemistry, University of Calgary, Alberta, Canada
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Andersen NG, Ramsden PD, Che D, Parvez M, Keay BA. A simple resolution procedure using the Staudinger reaction for the preparation of P-stereogenic phosphine oxides. J Org Chem 2001; 66:7478-86. [PMID: 11681964 DOI: 10.1021/jo015909u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The resolution of a variety of (+/-)-P-stereogenic phosphines is achieved by exploiting the Staudinger reaction of a (+/-)-phosphine with enantiopure (1S,2R)-O-(tert-butyldimethylsilyl)isobornyl-10-sulfonyl azide. The resulting mixtures of diastereomeric phosphinimines are generally separable by fractional crystallization or flash chromatography. Subsequent acid-catalyzed hydrolysis provides the corresponding optically pure phosphine oxides in high yields.
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Affiliation(s)
- N G Andersen
- Department of Chemistry, University of Calgary, Calgary, AB, Canada, T2N 1N4
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Chivers T, Krahn M, Parvez M, Schatte G. Steric effects on the mode of aggregation and reactivity of clusters formed from the lithiation of trisamidothiophosphates. Chem Commun (Camb) 2001:1922-3. [PMID: 12240220 DOI: 10.1039/b105360b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lithiation of SP[N(H)R]3 with LiBun produces the dimers [(THF)LiSP(NR)(NHR)2]2 (R = Pri) or ([LiSP(NR)-(NHR)2][(THF)LiSP(NR)2(NHR)])2 (R = But) with central Li2N2 or Li2S2 rings, respectively; further lithiation yields the dianion [SP(NR)2(NHR)]2- (R = Pri) or leads to sulfur extrusion when R = But.
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Affiliation(s)
- T Chivers
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
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Parvez M, Yadav VK, Balamurugan R. pi-Facial selectivities of diastereotopic ketones: p-bromobenzoates of 4-hetero-1-decalinols. Acta Crystallogr C 2001; 57:1084-8. [PMID: 11588379 DOI: 10.1107/s0108270101009544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2001] [Accepted: 06/08/2001] [Indexed: 11/11/2022] Open
Abstract
The crystal structures of the p-bromobenzoates of cis-4-oxa-1-decalinyl (C(16)H(19)BrO(3)), trans-4-oxa-1-decalinyl (C(16)H(19)BrO(3)), N-benzyl-cis-4-aza-1-decalinyl (C(23)H(26)BrNO(2)), N-benzyl-trans-4-aza-1-decalinyl (C(23)H(26)BrNO(2)) and trans-4-thia-1-decalinyl (C(16)H(19)BrO(2)S) (decalin is perhydronaphthalene) have been determined as part of a study directed at predicting and interpreting the pi-facial selectivities of diastereotopic ketones in reactions with nucleophiles. All five structures are composed of molecules that are separated by normal van der Waals distances. In all five structures, the heterocyclic and cyclohexyl rings adopt chair conformations, and the p-bromobenzoate groups are planar.
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Affiliation(s)
- M Parvez
- Department of Chemistry, The University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
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Chivers T, Krahn M, Parvez M, Schatte G. Preparation and x-ray structures of alkali-metal derivatives of the ambidentate anions [tBuN(E)P(mu-NtBu)2P(E)NtBu]2- (E = S, Se) and [tBuN(Se)P(mu-NtBu)2PN(H)tBu)]-. Inorg Chem 2001; 40:2547-53. [PMID: 11350233 DOI: 10.1021/ic001093o] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ambidentate dianions [(t)BuN(E)P(mu-N(t)Bu)(2)P(E)N(t)Bu](2)(-) (5a, E = S; 5b, E = Se) are obtained as their disodium and dipotassium salts by the reaction of cis-[(t)Bu(H)N(E)P(mu-N(t)Bu)(2)P(E)N(H)(t)Bu] (6a, E = S; 6b, E = Se), with 2 equiv of MN(SiMe(3))(2) (M = Na, K) in THF at 23 degrees C. The corresponding dilithium derivative is prepared by reacting 6a with 2 equiv of (t)BuLi in THF at reflux. The X-ray structures of five complexes of the type [(THF)(x)()M](2)[(t)BuN(E)P(mu-N(t)Bu)(2)P(E)N(t)Bu] (9, M = Li, E = S, x = 2; 11a/11b, M = Na, E = S/Se, x = 2; 12a, M = K, E = S, x = 1; 12b, M = K, E = Se, x = 1.5) have been determined. In the dilithiated derivative 9 the dianion 5a adopts a bis (N,S)-chelated bonding mode involving four-membered LiNPS rings whereas 11a,b and 12a,b display a preference for the formation of six-membered MNPNPN and MEPNPE rings, i.e., (N,N' and E,E')-chelation. The bis-solvated disodium complexes 11a,b and the dilithium complex 9 are monomeric, but the dipotassium complexes 12a,b form dimers with a central K(2)E(2) ring and associate further through weak K.E contacts to give an infinite polymeric network of 20-membered K(6)E(6)P(4)N(4) rings. The monoanions [(t)Bu(H)N(E)P(mu-N(t)Bu)(2)P(E)N(t)Bu)](-) (E = S, Se) were obtained as their lithium derivatives 8a and 8b by the reaction of 1 equiv of (n)BuLi with 6a and 6b, respectively. An X-ray structure of the TMEDA-solvated complex 8a and the (31)P NMR spectrum of 8b indicate a N,E coordination mode. The reaction of 6b with excess (t)BuLi in THF at reflux results in partial deselenation to give the monolithiated P(III)/P(V) complex [(THF)(2)Li[(t)BuN(Se)P(mu-N(t)Bu)(2)PN(H)(t)Bu]] 10, which adopts a (N,Se) bonding mode.
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Affiliation(s)
- T Chivers
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
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Kruhlak NL, Wang M, Boorman PM, Parvez M, McDonald R. Syntheses, structures, and stabilities of [PPh(4)][WS(3)(SR)](R=(i)Bu,(i)Pr,(i)Bu, benzyl, allyl) and [PPh(4)][MoS(3)(S(t)Bu)]. Inorg Chem 2001; 40:3141-8. [PMID: 11399185 DOI: 10.1021/ic000970n] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intermediates in the condensation process of [MS(4)](2)(-) (M = Mo, W) to polythiometalates, in the presence of alkyl halides, had not been reported prior to our communication of [PPh(4)][WS(3)(SEt)] (Boorman, P. M.; Wang, M.; Parvez, M. J. Chem. Soc., Chem. Commun. 1995, 999-1000). We now report the isolation of a range of related compounds, with 1 degrees, 2 degrees, and 3 degrees alkyl thiolate ligands, including one Mo example. [PPh(4)][WS(3)(SR)] (R = (i)Bu (1), (i)Pr (2), (t)Bu (3), benzyl (5), allyl (6)) and [PPh(4)][MoS(3)(S(t)Bu)] (4) have been isolated in fair to good yields from the reaction of [PPh(4)](2)[MS(4)] with the appropriate alkyl halide in acetonitrile and subjected to analysis by X-ray crystallography. Crystal data are as follows: for 1, triclinic space group P1 (No. 2), a = 11.0377(6) A, b = 11.1307(5) A, c = 13.6286(7) A, alpha = 82.941(1) degrees, beta = 84.877(1) degrees, gamma = 60.826(1) degrees, Z = 2; for 2, monoclinic space group P2(1)/c (No. 14), a = 9.499(6) A, b = 15.913(5) A, c = 18.582(6) A, beta = 99.29(4) degrees, Z = 4; for 3, monoclinic space group P2(1)/n (No. 14), a = 10.667(2) A, b = 17.578(2) A, c = 16.117(3) A, beta = 101.67(1) degrees, Z = 4; for 4, monoclinic space group P2(1)/n (No. 14), a = 10.558(3) A, b = 17.477(3) A, c = 15.954(3) A, beta = 101.18(2) degrees, Z = 4; for 5, monoclinic space group P2(1)/n (No. 14), a = 16.2111(9) A, b = 11.0080(6) A, c = 18.1339(10) A, beta = 111.722(1) degrees, Z = 4; for 6, triclinic space group P1 (No. 2), a = 9.4716(9) A, b = 10.4336(10) A, c = 14.4186(14) A, alpha = 100.183(2) degrees, beta = 90.457(2) degrees, gamma = 91.747(2) degrees, Z = 2. Structures 3 and 4 are isomorphous, and 1 exhibits disorder about the tertiary carbon. 6 has been shown to exhibit fluxionality in solution by variable-temperature (1)H NMR studies, and an allyl migration mechanism is implicated in this process. The kinetics for the reaction of [WS(4)](2)(-) and EtBr were measured and suggest an associative nucleophilic substitution (S(N)2) mechanism. The decomposition of the [WS(3)(SEt)](-) ion is shown to be second order with respect to this ion, suggesting the formation of a transient binuclear intermediate. M-S bond cleavage is the predominant step in decomposition of 1-6 to yield alkyl sulfides, alkyl thiols, and polythiometalates such as [PPh(4)](2)[M(3)S(9)]. In contrast, reactions of [PPh(4)](2)[WO(x)()S(4)(-)(x)()] (x = 1, 2) with (t)BuBr result in the additional decomposition product of isobutene, presumably by C-S bond cleavage and beta-hydrogen transfer. Interestingly, the reaction of [PPh(4)](2)[WOS(3)] with BzCl yields 5 as the only isolable W thiolate species.
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Affiliation(s)
- N L Kruhlak
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada, T2N 1N4
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Parvez M, Senthil G, Yadav VK. 7-Phenyl-1-oxa-4-thiaspiro[4.5]decan-7-ol stereoisomers. Acta Crystallogr C 2001; 57:577-9. [PMID: 11353257 DOI: 10.1107/s0108270101001573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2000] [Accepted: 01/22/2001] [Indexed: 11/10/2022] Open
Abstract
The stereoisomers of 7-phenyl-1-oxa-4-thiaspiro[4.5]decan-7-ol, C(14)H(18)O(2)S, have the same stereochemistry at the C atom bearing an OH group, i.e. axial OH and equatorial phenyl groups. However, the acetal S and O atoms are axial and equatorial, respectively, in one isomer and reversed in the second. Furthermore, the crystals of one isomer are composed of hydrogen-bonded molecules involving the hydroxyl H atom and the O atom of the five-membered heterocyclic ring, with an O.O distance of 2.962 (3) A, forming a polymeric chain along the b axis. The asymmetric unit of the other isomer is composed of two molecules, wherein hydroxyl H atoms and the O atoms of the five-membered heterocyclic rings display intramolecular O-H.O hydrogen bonds with O.O separations of 2.820 (2) and 2.834 (2) A.
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Affiliation(s)
- M Parvez
- Department of Chemistry, The University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
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Chivers T, Fedorchuk C, Krahn M, Parvez M, Schatte G. Preparation and X-ray structures of Cu(I), Ni(II), and Pd(II) (N,S) complexes of the monoanion [(tBuN)(S)P(mu-N(t)Bu)2P(S)(NH(t)Bu)]- and a Pt(II) (S,S') complex of the dianion [((t)BuN)(S)P(mu-N(t)Bu)2P(S)(N(t)Bu)]2-. Inorg Chem 2001; 40:1936-42. [PMID: 11312752 DOI: 10.1021/ic001173s] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The metathetical reactions of the lithium derivative of the monoanion [((t)BuN)(S)P(mu-N(t)Bu)(2)P(S)(NH(t)Bu)](-) (L) with CuCl/PPh(3), NiCl(2)(PEt(3))(2), PdCl(2)L'(2) (L' = PhCN, PPh(3)), and PtCl(2)(PEt(3))(2) produced the complexes (PPh(3))CuL (5), NiL(2) (6), PdCl(L)(PPh(3)) (7), PdL(2) (8), and Pt(PEt(3))(2)[((t)BuN)(S)P(mu-N(t)Bu)(2)P(S)(N(t)Bu)] (9). The X-ray structures of 5, 6, and 8 reveal a N,S-coordination for the chelating monoanion L with the metal centers in trigonal planar, tetrahedral, and square planar environments, respectively. By contrast, the dianionic ligand in the square planar Pt(II) complex 9 is S,S'-chelated to the metal center. (31)P NMR spectra readily distinguish between the N,S and S,S' bonding modes, and, on that basis, N,S chelation is inferred for the Pd(II) complex 7. Crystal data: 5, monoclinic, P2(1)/c, a = 19.175(4) A, b = 20.331(4) A, c = 10.017(6) A, beta = 91.79(3) degrees, V = 3903(2) A(3), and Z = 4; 6, orthorhombic, Pbcn, a = 14.298(5) A, b = 15.333(5) A, c = 24.378(5) A, beta = 90.000(5) degrees, V = 5344(3) A(3), and Z = 4; 8, monoclinic, P2(1)/n, a = 13.975(3) A, b = 14.283(3) A, c = 15.255(4) A, beta = 116.565(18) degrees, V = 2723.5(11) A(3), and Z = 2; 9, monoclinic, P2(1)/n, a = 12.479(6) A, b = 21.782(7) A, c = 17.048(5) A, beta = 100.30(3) degrees, V = 4559(3) A(3), and Z = 4.
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Affiliation(s)
- T Chivers
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
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Chivers T, Downard A, Parvez M, Schatte G. The many guises of lithium chloride: crystal structure of the single-strand polymer [LiCl.2MeCn](infinity). Inorg Chem 2001; 40:1975-7. [PMID: 11312757 DOI: 10.1021/ic001175c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- T Chivers
- Department of Chemistry, University of Calgary, 2500 University Drive, Calgary, Alberta, Canada T2N 1N4.
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Abstract
The structure of the title compound, 2-[1-(dimethylammonioethoxy)-1-phenylethyl]pyridinium tetrachlorocuprate(II), (C(17)H(24)N(2)O)[CuCl(4)], contains dihydro cations of doxylamine hydrogen bonded to two Cl atoms in two different [CuCl(4)](2-) anions, with Cl...N distances of 3.101 (9) and 3.253 (10) A. The ethereal O atom is involved in intramolecular hydrogen bonds, with O.N distances of 2.517 (11) and 2.757 (12) A. The molecular dimensions in the cation are as expected and the [CuCl(4)](2-) anion has a flattened tetrahedral geometry.
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Affiliation(s)
- K Braitenbach
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
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Chivers T, Parvez M, Schatte G. Lithium halide adducts of imidotellurium(IV) ligands: synthesis and X-ray structures of [Li(THF)2L](mu 3-I)[LiI(L)] [L = tBuNTe(mu-NtBu)2TeNtBu] and [(THF)3Li3(mu 3-I)(Te(NtBu)3)]. Inorg Chem 2001; 40:540-5. [PMID: 11209613 DOI: 10.1021/ic000785+] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction of the chelating ligand tBuNTe(mu-NtBu)2TeNtBu (L) with LiI in THF yields [Li(THF)2L](mu 3-I)[LiI(L)] (3). This complex is also formed by the attempted oxidation of [Li2Te(NtBu)3]2 with I2. An X-ray analysis of 3 reveals that the tellurium diimide dimer acts as a chelating ligand toward (a) [Li(THF)2]+ cations and (b) a molecule of LiI. An extended structure is formed via weak Te...I interactions [3.8296(7)-3.9632(7) A] involving both mu 3-iodide counterions and the iodine atoms of the coordinated LiI molecules. Crystal data: 3, triclinic, space group P1, a = 10.1233(9) A, b = 15.7234(14) A, c = 18.8962(17) A, alpha = 86.1567(16) degrees, beta = 84.3266(16) degrees, gamma = 82.9461(16) degrees, V = 2965.8(5) A3, Z = 2. The oxidation by air of [Li2Te(NtBu)3]2 in toluene produces the radical (Li3[Te(NtBu)3]2), which exhibits an ESR spectrum consisting of a septet of decuplets (g = 2.00506, a(14N) = 5.26 G, a(7Li) = 0.69 G). The complexes [(THF)3Li3(mu 3-X)(Te(NtBu)3)] (4a, X = Cl; 4b, X = Br; 4c, X = I) are obtained from the reaction of [Li2Te(NtBu)3]2 with lithium halides in THF. The iodide complex, 4c, has a highly distorted, cubic structure comprised of the pyramidal [Te(NtBu)3]2- dianion which is linked through three [Li(THF)]+ cations to I- Crystal data: 4c, triclinic, space group P1, a = 12.611(8) A, b = 16.295(6) A, c = 10.180(3) A, alpha = 98.35(3) degrees, beta = 107.37(4) degrees, gamma = 108.26(4) degrees, V = 1829(2) A3, Z = 2.
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Affiliation(s)
- T Chivers
- Department of Chemistry, University of Calgary, 2500 University Drive N.W., Calgary, Alberta, Canada T2N 1N4.
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Abstract
The structure of ¿3-[(4-fluorophenyl)methyl]-1H-benzimidazol-2-ylidene¿¿1-[2-(4- methox yphenyl)ethyl]-4-piperidin-1-io¿ammonium tetrachlorocuprate(II), (C(28)H(33)FN(4)O)[CuCl(4)], contains diprotonated cations of astemizole hydrogen bonded to three Cl atoms in two different CuCl(4)(2-) anions, with Cl.N distances in the range 3.166 (4)-3.203 (4) A. The geometry around copper is flattened tetrahedral with significantly different Cu-Cl distances which lie in the range 2.1968 (14)-2.2861 (12) A. The phenylethyl C atoms of the (4-methoxyphenyl)ethyl group are disordered indicating the presence of two conformers in the crystals.
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Affiliation(s)
- M Parvez
- Department of Chemistry, The University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
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Abstract
[structure: see text] A short five-step synthesis of (+/-)-2,2'-bis(diphenylphosphino)-3, 3'-binaphtho[2,1-b]furan (BINAPFu, 1) starting from 2-naphthoxyacetic acid is reported. The resolution of BINAPFu 1 was possible using our newly developed resolution procedure for phosphines wherein (1S)-camphorsulfonyl azide was used to prepare the bisphosphinimine of BINAPFu via the Staundinger reaction. BINAPFu consistently outperformed BINAP in an asymmetric Heck reaction between 2,3-dihydrofuran and phenyl triflate.
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Affiliation(s)
- N G Andersen
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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Abstract
X-ray crystallography of bisline, and the chemical interconversion of bisline and isoline (ruwenine), revealed that the structures previously assigned to these alkaloids required revision; as did that of isolinecic acid.
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Affiliation(s)
- L Susag
- Chemistry Department, University of Calgary, Alta., Canada
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Abstract
The structure of dichloro[1-(p-chlorobenzyl)-2-(1-pyrrolidinylmethyl-N)-1, 3-benzimidazole-N(3)]cobalt(II), [CoCl(2)(C(19)H(20)ClN(3))], contains a molecule of clemizole bound in a bidentate manner to cobalt through its imidazole and pyrrolidinyl N atoms, with significantly different Co-N distances of 1.976 (5) and 2.126 (5) A, respectively. The geometry around cobalt is distorted tetrahedral, with significantly different Co-Cl distances of 2.217 (2) and 2.233 (2) A, and the pyrrolidinyl ring is disordered.
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Affiliation(s)
- M Parvez
- Department of Chemistry, The University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada.
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44
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Affiliation(s)
- M Parvez
- Department of Chemistry, University of Calgary, Alberta, Canada.
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Brask JK, Chivers T, Parvez M. Polylithiated tetraaminosilanes: synthesis and characterization of (Et2O.Li)4[Si(Nnaph)4] and X-ray structure of (THF.Li3[Si(NiPr)3(NHiPr)])2. Inorg Chem 2000; 39:2505-8. [PMID: 11197002 DOI: 10.1021/ic991238v] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The treatment of SiCl4 with 4 equiv of Li2(Nnaph) (naph = 1-naphthyl) in diethyl ether gives (Et2O.Li)4[Si(Nnaph)4] (4), which, upon reaction with excess tBuNH3Cl or MeO3SCF3, generates Si[N(H)naph]4 (5) or Si[N(Me)naph]4 (6), respectively. The centrosymmetric dimer (THF.Li3[Si(NiPr)3(NHiPr)])2 (7), formed via trilithiation of Si[N(H)iPr]4 with n-butyllithium, consists of a bis-THF-solvated Li6(NiPr)6 cyclic ladder bicapped by two SiN(H)iPr units. Crystal data for 7: C32H74Li6N8O2Si2, monoclinic, P2(1)/n, a = 10.661(7) A, b = 16.964(5) A, c = 12.405(4) A, beta = 93.22(4) degrees, V = 2239.9(15) A3, and Z = 2.
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Affiliation(s)
- J K Brask
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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Chivers T, Gibson MP, Parvez M, Vargas-Baca I. Eight- and 16-membered cyanuric-sulfanuric ring systems: C2N4S2-->C2N3S ring contraction. Inorg Chem 2000; 39:1697-704. [PMID: 12526556 DOI: 10.1021/ic991314u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Eight- and 16-membered cyanuric-sulfanuric ring systems of the type Ar2C2N4S2(O)2Ar'2 (3a, Ar = 4-BrC6H4, Ar' = Ph; 3b, Ar = 4-CF3C6H4, Ar' = Ph; 3c, Ar = 4-CF3C6H4, Ar' = 4-CH3C6H4) and Ar4C4N8S4(O)4Ar'4 (4b, Ar = 4-CF3C6H4, Ar' = Ph; 4c, Ar = 4-CH3C6H4, Ar' = Ph; 4d, Ar = 4-CF3C6H4, Ar' = 4-CH3C6H4), respectively, were prepared in good yields by the reaction of the corresponding sulfur(IV) systems with m-chloroperbenzoic acid. The X-ray structures of 3b, 3c.C7H14, 4b.CH2Cl2, 4c, and the S(IV) system Ar4C4N8S4Ar'4 (2c, Ar = 4-CH3C6H4, Ar' = Ph) were determined. Upon oxidation the two oxygen atoms in 3b and 3c.C7H14 adopt endo positions leading to a twist boat conformation for the C2N4S2 ring. The 16-membered C4N8S4 rings in 4b and 4c retain a cradle conformation upon oxidation. The S-N bond distances are ca. 0.06 A shorter in all the S(VI) systems compared to those in the corresponding S(IV) rings. The thermolysis of 3b at ca. 220 degrees C occurs primarily via loss of a sulfanuric group, NS(O)Ph, to give the six-membered ring (4-CF3C6H4)2C2N3S(O)Ph (6). The structure of 6 was confirmed by X-ray crystallography. Crystal data: 2c, triclinic, space group P1 with a = 13.917(2) A, b = 15.610(4) A, c = 13.491(3) A, alpha = 95.77(2) degrees, beta = 114.82(1) degrees, gamma = 76.21(2) degrees, V = 2583(1) A3, and Z = 2; 3b, monoclinic, space group P2(1)/a with a = 7.316(2) A, b = 29.508(5) A, c = 12.910(2) A, beta = 101.30(2) degrees, V = 2733(1) A3, and Z = 4; 3c.C7H14, triclinic, space group P1 with a = 12.849(4) A, b = 12.863(4) A, c = 12.610(7) A, alpha = 110.61(3) degrees, beta = 105.77(3) degrees, gamma = 62.77(2) degrees, V = 1719(1) A3, and Z = 2; 4b.CH2Cl2, triclinic, space group P1 with a = 12.647(3) A, b = 19.137(3) A, c = 12.550(2) A, alpha = 105.765(11) degrees, beta = 93.610(15) degrees, gamma = 88.877(16) degrees, V = 2917.2(9) A3, and Z = 2; 4c, orthorhombic, space group Pba2 with a = 22.657(2) A, b = 10.570(2) A, c = 10.664(3) A, alpha = beta = gamma = 90 degrees, V = 2554(1) A3, and Z = 2; 6, triclinic, space group P1 with a = 7.4667(8) A, b = 11.3406(12) A, c = 13.5470(14) A, alpha = 108.000(2) degrees, beta = 105.796(2) degrees, gamma = 94.300(2) degrees, V = 1033.8(2) A3, and Z = 2.
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Affiliation(s)
- T Chivers
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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Abstract
The crystal structure of caulerpin (dimethyl 6,13-dihydrodibenzo[b,i]phenazine-5,12-dicarboxylate, C(24)H(18)N(2)O(4)), an indole alkaloid, reported in space group Cc with an acute beta angle, has been redetermined in the correct space group, C2/c. The molecule has twofold crystallographic symmetry and is composed of two essentially planar indole groups fused to an eight-membered cyclooctatetraene ring which adopts a boat conformation. The molecular dimensions are normal. The structure is stabilized by intermolecular and intramolecular interactions involving the indole N-H atom and carbonyl O atom [N.O 3.211 (4) and 2.836 (4) A].
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Affiliation(s)
- M Parvez
- Department of Chemistry, The University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
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Affiliation(s)
- JK Brask
- Department of Chemistry University of Calgary Calgary, Alberta T2N 1N4 (Canada)
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Parvez M, Bhatti MH, Ali S, Mazhar M, Qureshi SI. (N-maleoylglycinato)trimethyltin(IV). Acta Crystallogr C 2000; 56 ( Pt 3):327-8. [PMID: 10777937 DOI: 10.1107/s0108270199016510] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/1999] [Accepted: 12/17/1999] [Indexed: 11/10/2022] Open
Affiliation(s)
- M Parvez
- Department of Chemistry, University of Calgary, Alberta, Canada.
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Parvez M, Choudhary MI, Parveen S, Ayatollahi SA. Cyclomicrobuxine monohydrate. Acta Crystallogr C 2000; 56 ( Pt 2):233-4. [PMID: 10777899 DOI: 10.1107/s0108270199014420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/1999] [Accepted: 11/08/1999] [Indexed: 11/10/2022] Open
Affiliation(s)
- M Parvez
- Department of Chemistry, University of Calgary, Alberta, Canada.
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